Effect of Breast Milk Circadian Properties on Infant's Growth Parameters and Absorption of Nutrients

The most ideal method for providing breast milk is breastfeeding. However, it may be necessary to express breast milk for reasons such as the newborn being in an intensive care unit, the mother being hospitalized for any reason, or the mother starting to work. The content of breast milk varies according to gestational age and stages of lactation. However, it varies from day to day depending on the infant's needs. In recent literature, it is emphasized that the content of breast milk (carbohydrates, fats, proteins, vitamins, trace elements, etc.) varies according to circadian variation. In the literature review, no national or international study was found indicating whether the circadian properties of breast milk have an effect on the infant's growth parameters. This study was designed as a randomized controlled experimental study to determine the effect of the circadian properties of breast milk on the growth parameters of the infant and the absorption levels of nutrients by the baby in preterm newborns. no effect on the infant's growth parameters and nutrient absorption levels by the infant. Hypothesis 1 (H1): Feeding preterm newborns with breast milk according to the circadian rhythm has an effect on the weight of the infants. Hypothesis 2 (H2): Feeding preterm newborns with breast milk according to the circadian rhythm has an effect on the height of the infants. Hypothesis 3 (H3): Feeding preterm newborns with breast milk according to the circadian rhythm has an effect on the head circumference of the infants. Hypothesis 4 (H4): Feeding preterm newborns with breast milk according to the circadian rhythm has an effect on the absorption levels of vitamins and trace elements measured in the infants' breast milk.

Breast milk is an ideal and unique food with excellent content for the healthy growth and development of both term and preterm babies. Breast milk, which is considered the "Gold Standard" in term and preterm baby nutrition, has a complex, lively and dynamic structure. The content of breast milk varies from day to day and according to the gestational age, stages of lactation, and the baby's needs. These differences indicate that breast milk is a unique food. Breast milk contains many complex nutrients, and while the amount of some nutrients varies depending on the mother's diet, lactation day and duration, some nutrients remain at relatively constant levels. Breast milk contains macronutrients (carbohydrates, proteins, fats), micronutrients (vitamins, trace elements and electrolytes) and bioactive factors (various hormones, immune factors and other bioactive factors). In recent years, the difference in the content of breast milk according to circadian variation has been evaluated. In studies examining breast milk content according to circadian variation, it was stated that total carbohydrate concentration did not show circadian change.It has been determined that the fat concentrations in breast milk, which are necessary for the growth and development of the baby, indicate the existence of circadian variation. However, there are different results in element and vitamin studies. In cases where breast milk should be given by expressing, not giving milk in accordance with the circadian rhythm may disrupt the developing circadian rhythms of babies, potentially causing sleep problems and decreased physiological harmony with their parents/environment. This situation may negatively affect the baby's growth and development and endanger its health. In light of this information; The study was planned to determine the effect of the circadian properties of breast milk on the growth parameters of the baby and the absorption levels of nutrients by the baby in preterm newborns.